Product options

Almost all of our speakers are made in 8 ohm and 20 ohm and with transformer as standard products. You will notice that the speaker names in all of our datasheets has a (T) in them (HP-20 T). The T in our product names means that it is is the transformer version. If you want to order a speaker in 8 ohm, omit the T (HP-20, 8 ohm).
Horn speakers can be cusomized in all kinds of impedances from 2 – 50 ohm or more.


Ask us about specialities and modifications! We can for instance modify:

  • Color
  • Extra gland
  • Gland placement
  • Volume control
  • Cabling
  • Transformer tapping

What is ATEX

Atex stands for ATmospheres EXplosibles “potentially explosive atmospheres”. Explosive atmospheres can be caused by:

  • Flammable gases
  • Mists
  • Vapours
  • Combustible dusts.

IP Degree of Protection?

First figure

Second figure


No protection


No protection


Protected against a solid object 50 mm or greater


Protected against vertically dripping water


Protected against a solid object 12 mm or greater


Protected against vertically dripping water, when tilted 15 degrees


Protected against a solid object 2,5 mm or greater


Protected against water spraying at an angle up to 60 degree


Protected against a solid object 1 mm or greater


Protected against water splashing from any direction


Dust protected


Protected against jets of water from any directions


Dust tight


Protected against powerful jets of water from any directions


Protected against immersion between a depth of 150 mm and 1000 mm


Protected against submersion

Explosive Atmosphere

Explosion Protection

An explosive atmosphere is built up by a mixture of flammable gases, vapours, mists or dust with atmosphere air. If the mixture (flammable material/air) has the right ratio it can be an ignition source and create an explosion.


Factors for creating an explosion:


  1. Air (or in fact oxygen in the air)
  2. Flammable material (substance)
  3. Ignition source

100V systems?

100V Line speaker systems are sometimes referred to as “constant-voltage system” it is the most economical way to install a multi-speaker sound system. The term 100V system relates to the maximum output voltage of the amplifier. To generate this high voltage the amplifier is equipped with a step-up transformer, which increases the normal output voltage of around 30 Volts, up to 100 Volts


The main difference between a low-impedance speaker system (4 or 8 Ohms) is the way the individual loudspeakers are connected to the amplifier, with the conventional low-impedance system special care has to be taken to maintain the correct impedance for the amplifier.


In a 100V line system, a large number of single loudspeakers each equipped with a step-down transformer can be connected to one single speaker cable. With the 100V line installation, each speaker or speaker cabinet is equipped with a step-down transformer


A step-down transformer has relatively high impedance at the primary side and the secondary side of the transformer matches the speaker impedance (typically 8 Ohms). The primary side of the transformer normally has several tapping’s, these are marked in watts and are used to enable each speaker to be set at different volume levels. The total primary wattage should not exceed 90% of the amplifiers output. A step-down transformer will be required for each loudspeaker cabinet connected to the amplifier.

Where can I check reference projects for DNH loudspeakers?

For reference projects with DNH loudspeakers contact Bart Derks by email, or call +31 (0)24-3667474

Theunissen Technical Trading Benelux importer for DNH

Rijksweg 191, 6581 EK
Malden, The Netherlands
Phone: +31 (0)24-3584455
E-mail: info@tttbv.com